U.S. patent application number 14/952316 was filed with the patent office on 2017-05-25 for plugs including insert for composite threaded mandrel for downhole applications.
This patent application is currently assigned to Baker Hughes Incorporated. The applicant listed for this patent is Zachary S. Silva. Invention is credited to Zachary S. Silva.
Application Number | 20170145776 14/952316 |
Document ID | / |
Family ID | 58719463 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170145776 |
Kind Code |
A1 |
Silva; Zachary S. |
May 25, 2017 |
PLUGS INCLUDING INSERT FOR COMPOSITE THREADED MANDREL FOR DOWNHOLE
APPLICATIONS
Abstract
An apparatus for use in a wellbore is disclosed that in one
non-limiting embodiment includes a mandrel having a recess on a
lower section thereof, a packing element around the mandrel,
wherein the packing element provides a seal between the apparatus
and the wellbore when the packing element is expanded radially
outward from the mandrel; and a threaded member having a threaded
outer surface placed around the lower section of the mandrel, and
wherein strength of the threaded member is greater than the
strength of the lower section of the mandrel. The apparatus may
further include a guide member threaded on the threaded member to
provide support to the mandrel. The apparatus may be utilized as a
frac plug and a bridge plug.
Inventors: |
Silva; Zachary S.; (Houston,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Silva; Zachary S. |
Houston |
TX |
US |
|
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
58719463 |
Appl. No.: |
14/952316 |
Filed: |
November 25, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 33/134
20130101 |
International
Class: |
E21B 33/12 20060101
E21B033/12 |
Claims
1. An apparatus for use in a wellbore, comprising: a mandrel having
a lower section thereof; a packing element around the mandrel that
provides a seal between the packing element and the wellbore when
the packing element is set; and a threaded member having a threaded
outer surface placed around the lower section of the mandrel,
wherein strength of the threaded member is greater than the
strength of the lower section of the mandrel.
2. The apparatus of claim 1, wherein the lower section of the
mandrel includes a recess in the mandrel.
3. The apparatus of claim 2, wherein the mandrel threaded member
includes an indented section that mates with or substantially mates
with the recess in the lower section of the mandrel.
4. The apparatus of claim 2, wherein at least one edge of the
recess is one of: a vertical edge; a curved edge; and an angled
edge.
5. The apparatus of claim 1 further comprising a guide member
threaded onto the threaded member to provide support to the
mandrel.
6. The apparatus of claim 1, wherein the lower section of the
mandrel is made from a composite material.
7. The apparatus of claim 1, wherein the threaded member is made
from a material selected from a group consisting of: aluminum; cast
iron; phenolic; and multiple phenolics.
8. The apparatus of claim 1, wherein the threaded member is in
selected from a group consisting of: f a clam shell; and a collet,
each adapted to be placed around the lower section of the
mandrel.
9. A method of placing a plug in a wellbore, the method comprising:
conveying the plug by a string into the wellbore and locating the
plug at a selected location in the wellbore, the plug including a
mandrel having a recess on a lower section of the mandrel, a
packing element around the mandrel, wherein the packing element
provides a seal between the packing element and the wellbore, and a
threaded member having a threaded outer surface placed around the
lower section of the mandrel, and wherein strength of the threaded
member is greater than the strength of the lower section of the
mandrel; setting the packing element to form the seal between the
packing element and the wellbore; and performing an operation in
the wellbore.
10. The method of claim 9, wherein the threaded member includes an
indented section that substantially mates with the recess.
11. The method of claim 9, wherein the lower section of the mandrel
is made from a composite material.
12. The method of claim 9, wherein the threaded member is made from
a material selected from a group consisting of: aluminum; cast
iron; phenolic; and multiple phenolics.
13. The method of claim 9, wherein the threaded member is a clam
shell shaped member adapted to be placed around the lower section
of the mandrel with the indented section placed in the recess.
14. The method of claim 9, wherein the plug further includes a
guide member threaded onto the threaded member to protect the
threaded member during downhole operations.
15. The method of claim 9, wherein at least one edge of the recess
is one of: a vertical edge; and an angled edge.
16. A wellbore system, comprising: a plug placed at a selected
location in a casing in the wellbore, wherein the plug includes: a
packing element around a mandrel that provides a seal between the
packing element and the casing when the packing element is set; and
a threaded member having a threaded outer surface placed around a
lower section of the mandrel, wherein strength of the threaded
member is greater than the strength of the lower section of the
mandrel.
17. The wellbore system of claim 16, wherein the lower section of
the mandrel includes a recess.
18. The wellbore system of claim 17, wherein the threaded member
includes an indented section that mates with or substantially mates
with the recess in the lower section of the mandrel.
19. The wellbore system of claim 18, wherein at least one edge of
the recess is one of: a vertical edge; a curved edge; and an angled
edge.
20. The wellbore system of claim 16 further comprising a guide
member threaded onto the threaded member to provide support to the
mandrel, wherein the strength of the threaded member is same or
greater than the strength of the guide.
Description
BACKGROUND
[0001] 1. Field of the Disclosure
[0002] The disclosure relates generally to plugs and other devices
that utilize composite threaded members subjected to loads during
downhole applications.
[0003] 2. Background Art
[0004] Devices such as frac plugs and bridge plugs are commonly
utilized in wellbores to perform a variety of downhole operations.
Some such plugs include a composite threaded member, such as a
composite threaded mandrel, on which another member or device, such
as a guide is threaded, to protect the plug during run-in of the
plug in the wellbore and from other subsequent downhole conditions
or operations. The composite material often is a fiber-based
material, such as fiber glass. Often, the shear values of such
composite mandrels in some applications are insufficient to provide
pitch and wind angles for the threads able to withstand high loads
applied on such members during run-in and later wellbore
operations. A guide is typically made from a phenolic material with
internal threads that mate with the threads on the composite
mandrel. In some downhole applications, such threading arrangement
is not sufficient to protect the composite member. Therefore, there
is a need to provide downhole devices, such as plugs, that include
threaded composite members that can withstand higher loads than
contained in currently available devices, including, but not
limited to, frac plugs and bridge plugs.
[0005] The disclosure herein provides downhole devices that include
a threaded member placed around a recess on a composite member
possessing greater strength than the strength of the composite
member, so that the combination of the composite member and the
threaded member can absorb greater loads than loads the composite
member can absorb during downhole operations at present.
SUMMARY
[0006] An apparatus for use in a wellbore is disclosed that in one
non-limiting embodiment includes a mandrel having a recess on a
lower section thereof, a packing element around the mandrel,
wherein the packing element provides a seal between the apparatus
and the wellbore when the packing element is expanded radially
outward from the mandrel; and a threaded member having a threaded
outer surface placed around the lower section of the mandrel,
wherein strength of the threaded member is greater than the
strength of the lower section of the mandrel. The apparatus may
further include a guide member threaded on the threaded member to
provide support to the mandrel. The apparatus may be utilized as a
frac plug or a bridge plug.
[0007] In another aspect, a method of placing a plug in a wellbore
is disclosed that in one embodiment includes: conveying the plug by
a string into the wellbore and locating the plug at selected
location in the wellbore, wherein the plug includes a mandrel
having a recess on a lower section of the mandrel, a packing
element around the mandrel to provide a seal between the packing
element and the wellbore, and a threaded member having a threaded
outer surface placed around the lower section of the mandrel, and
wherein strength of the threaded member is greater than the
strength of the lower section of the mandrel; expanding the packing
element radially outward to form the seal between the packing
element and the wellbore; and performing an operation in the well
bore.
[0008] Examples of the more important features of an apparatus and
methods have been summarized rather broadly in order that the
detailed description thereof that follows may be better understood,
and in order that the contributions to the art may be appreciated.
There are, of course, additional features that will be described
hereinafter and which will form the subject of the claims.
DRAWINGS
[0009] For a detailed understanding of the apparatus and methods
disclosed herein, reference should be made to the accompanying
drawing and the detailed description thereof, wherein like elements
are generally given same numerals and wherein:
[0010] FIG. 1 is a perspective view of a plug for downhole
application, according to one embodiment of the disclosure;
[0011] FIG. 2 is a line diagram of the plug of FIG. 1 set and
activated in a casing in a well bore;
[0012] FIG. 3 is the plug of FIG. 2 set or activated in a casing in
the wellbore when used as a frac plug; and
[0013] FIG. 4 is the plug of FIG. 2 set or activated in a casing in
the wellbore when used as a bridge plug.
DETAILED DESCRIPTION
[0014] In general, the disclosure provides apparatus or devices for
downhole use, such as frac plugs and bridge plugs, that include a
threaded insert on a load-bearing composite member, such as a
mandrel of the plug, wherein strength (such as yield strength,
shear strength, etc.) of the threaded insert is greater than the
strength of the composite member. The combination of the composite
member and the threaded insert on the composite mandrel can
withstand loads greater than the devices that utilize threaded
composite members. In the case of plugs, the threaded insert
increases the shear area through the composite member and maintains
the composite length and continuity of the composite mandrel.
Should threads be formed on current composite mandrels for
placement of a thereon, as is commonly done, lacking the increased
shear area, the mandrel would be detrimentally affected. For ease
of explanation and understanding, the concepts of the disclosure
herein are described in reference to a non-limiting exemplary plug,
although such concepts are equally applicable to other downhole
devices. Therefore, the disclosure herein is not intended to be
limited to plugs.
[0015] FIG. 1 is a perspective view of a plug 100 made according to
a non-limiting embodiment of the disclosure. FIG. 2 is a line
diagram of the plug 100 placed and activated inside a casing 104
placed inside a wellbore 101 by a setting tool 190, which is
typically a string with a tubular 192 attached to the plug 100.
Various types of setting tools are known in the art and any
suitable setting tool may be utilized for the purpose of this
disclosure. Referring to FIGS. 1 and 2, the plug 100 in one aspect
may be utilized as a frac plug and in another aspect as bridge
plug. The plug 100 includes a mandrel 110 that includes a flow
through passage 112. The mandrel 110 further includes a seat 114
for landing a ball 116 therein after the plug has been set or
deployed in the wellbore. A sealing device 120 (such as a packer)
is disposed around the mandrel 110 to set the plug 100 in the
casing 104. The sealing device 120 includes an upper slip 122a and
a lower slip 122b. A packing element 126 is placed on around the
mandrel 110 between the upper slip 122a and the lower slip 122b. An
upper load ring 124 is provided above the upper slip 122a to
activate or expend the packing element 126 to engage with the
casing 104. A shear member, such as a ring 128, along with a shear
washer 129, are provided above the upper slip 122a. The shear ring
128 shears off during setting of the plug 100 in the casing 104 and
is retrieved from the wellbore 101 when the setting tool 190 is
retrieved from the wellbore 101. In one non-limiting embodiment,
the mandrel 110 is made from a composite material, which may be a
fibrous material, including, but not limited to, fiber glass. A
lower section or portion 150a of the mandrel 110 has a diameter
D.sub.1 smaller than the diameter D.sub.2 of the upper section
150b. The lower section 150a further includes one or more recesses
or notches, such as notch 160. A threaded member 170, having outer
threads 172 and an indented section 174, is placed around the lower
section 150a of the mandrel 110. The indented section 174 mates
with or conforms to or substantially conforms to the recess 160.
Thus, the indented section 174 of the threaded member 170 seats
inside the recess 160 and the threads 172 are exposed to the
environment. A suitable guide 180 may be threaded onto the threads
172 of the member 170. In one aspect, the material of the threaded
member 170 has a yield strength greater than the yield strength of
the material of at least the lower section 150a of the mandrel 110.
In another aspect, the material of the threaded member 170 has
hardness greater than the hardness of the material of at least the
lower section 150a of the mandrel 110. Also, in aspects, the
material of the threaded member 170 is at least as strong as the
material of the guide 180. Thus, the higher strength material of
threaded member 170 allows the use of a higher strength guide 180
compared to a mandrel with threads thereon for mating with the
guide 180. The member 170 is an insert that may be configured in
any suitable shape for placement around the lower section 150a of
the mandrel 110. In one embodiment, the member 170 may be in the
form of a clam shell that can be placed around the mandrel lower
section 150a. The insert 170 may include more than two axial
members, each configured to be placed around the lower section 150a
of the mandrel in a manner that will enable a device, such as guide
180 having internal threads, to mate with the thread 172 on the
member 170. The member 170 may be made from any suitable material,
including, but not limited to, phenolic, a metal or alloy,
including, but not limited to, aluminum and cast iron.
[0016] In the embodiments described above, the insert member 170 on
an otherwise composite mandrel acts to increase the shear area
through the mandrel and also maintains fiber length continuity of a
fibrous material mandrel that would otherwise be detrimentally
affected by cutting threads through the composite material. The
insert 170 acts as a threaded interface between the mandrel and a
threaded mating component, such as guide 180, for downhole
composite devices applications. For example, for a composite frac
plug that includes a filament wound mandrel and a phenolic lower
guide, the phenolic guide may shear the filament threads.
Filament-wound threads suffer in this regard because they must be
machined after the mandrel has been wound, which in effect reduces
the strength that the wind angles produce, because those continuous
fibers are cut in order to form the thread.
[0017] The recess 160 is provided in the outer diameter of the
mandrel 110 at a distance from the end 110a that will satisfy a
desired shear area. A clamshell of material that is at least as
strong as the box mating component is then fit into this recess
160, and have threads that extend to the end 110a. The mating guide
180 can then be threaded onto the threaded member (clamshell or
another configuration). All tensile loads between the mandrel 110
and the lower guide 180 goes from the lower guide thread 181 to the
clamshell thread 172, which is equal to or greater than the
strength of the lower guide threads 181, and then transmitted to
the increased shear plane of the mandrel. The edges 182a and 182b
of the recess 180 do need not be perpendicular to axis, and the
threads 172 may be of any form or pitch. Member 170 may be made
from multiple composites or a collet type construction, material
does not have to be limited to molded phenolic or filament-wound
fiber for the above mentioned description.
[0018] Still referring to FIGS. 1 and 2, to set the plug 100 at a
desired location, the string 190 with the plug 100 attached to a
bottom end of a tubular 192 is conveyed into the wellbore 101.
Fluid 103 under pressure is applied to the setting tool 190, which
causes the slips 122a and 122b move over their respective cones
123a and 123b, pushing the packing element 126 radially outward,
until the packing element 126 is forced against inside of the
casing 104 in the wellbore 101, as shown in FIG. 2. The upper load
ring 129 prevents the slip 122a from moving upward or uphole.
Setting of the packing element 126 against the casing 104 creates a
spacing "L" between the bottom of the slip 122b and the upper end
184 of the guide 180, as shown in FIG. 2.
[0019] The use of the plug 100 as a frac plug is shown in FIG. 3,
while the use of the plug 100 as a bridge plug is shown in FIG. 4.
For frac plug applications, a ball 116 is dropped from the surface
after the plug 100 has been set in the wellbore, which ball seats
or lodges in the seat 114 and blocks flow of fluid 301 supplied
from the surface through the passage 112 in the mandrel 110. This
allows a desired fluid, such as fracing fluid, to be supplied to a
desired location in the formation above the ball 116. To use the
plug 100 as a bridge plug, the passage 112 is removed from the
mandrel, as shown in FIG. 4, and when pressure is applied downhole
of the packing element 126, the guide 160 moves upward until its
upper end 184 of the guide 180 comes in contact with the slip
122b.
[0020] The foregoing disclosure is directed to the certain
exemplary non-limiting embodiments. Various modifications will be
apparent to those skilled in the art. It is intended that all such
modifications within the scope of the appended claims be embraced
by the foregoing disclosure. The words "comprising" and "comprises"
as used in the claims are to be interpreted to mean "including but
not limited to". Also, the abstract is not to be used to limit the
scope of the claims.
* * * * *